🚀 go-pugleaf

In article <45bj5r$pku@ae-sun01.alden.com>, sgr@ae-sun01.alden.com (Stan Ryckman) writes:
> I would think that it is impossible to satisfy a presumption for
> 1996-04-07 02:30:00 E?T
> where "?" is "D" or "S", for example.  That time does not exist
> in the U.S. (except in areas that are on year-round EST).
> [Or is it 01:30?  Now I've forgotten the exact rule  :-(  ]

My point was that a presumption is taking something for granted; a
presumption may be correct or incorrect, but it's not something to be
satisfied.  When you ask mktime to convert 1996-04-07 01:30:00 EST, it
presumes that Daylight Saving Time is/was not in effect then, consults
its DST rules, finds that DST *should* be in effect, and canonicalizes
the time to 1996-04-07 02:30:00 EDT.  Similarly, when you ask mktime to
convert 1996-04-07 01:30:00 EDT, it presumes that DST is/was in effect
then, consults the rules, finds that is should not be, and canonicalizes
to 1996-04-07 00:30:00 EST.  If you ask mktime to convert 1996-04-07
01:30:00 E?T (i.e., tm_isdst == -1), them mktime has a quandry since
neither 01:30:00 EST nor 01:30:00 EDT actually exists.  In that case
mktime is at liberty to arbitrarily pick one or the other, or to fail.
The case for 1995-10-29 01:30:00 E?T where both 01:30:00 EST and
01:30:00 EDT exist is similar.
----
Larry Jones, SDRC, 2000 Eastman Dr., Milford, OH  45150-2789  513-576-2070
larry.jones@sdrc.com
Let's pretend I already feel terrible about it, and that you
don't need to rub it in any more. -- Calvin